This section provides background information related to the present disclosure which is not necessarily prior art. This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
This solid state neutron detector fills a gap for sensitive compact and wearable sensors for homeland security applications. The potential applications include detection, identification and verification of special nuclear materials (plutonium and highly enriched uranium and others) which emit neutrons at characteristic unique energies. The device can be deployed at border posts and truck crossings to detect illicit traffic of nuclear weapon grade material. The solid state detector is a possible replacement for current He-3 gas based detectors which are extremely expensive, bulky, and unsustainable, because the He-3 gas supply is dwindling with no plans to produce more. The solid state neutron detector is very compact (cell-phone size) and can be worn as a real time dosimeter by first responders, nuclear power workers, airline flight crew, and military personnel. Real time wearable neutron dosimetry is not possible with bulky gas-based detectors. Another potential market space is down-hole gas and shale oil prospecting, where He-3 neutron detectors are currently used to measure hydrocarbon yield in oil-bearing shales.
The design is much more compact than current gas-based and scintillator neutron-detection approaches, potentially enabling a transformative detector development, namely wearable real-time neutron dosimetry for homeland security applications. The technical objectives of the present teachings are to quantitatively benchmark the proposed design against existing neutron detector approaches, to evaluate the efficiency and sensitivity of the design, and to evaluate its gamma-ray: neutron discrimination capabilities.
Evaluation of the neutron:gamma discrimination characteristics includes a thorough quantitative assessment of the detector front-end material response to neutron radiation and evaluation of its optoelectronic characteristics. The invention is a novel disruptive neutron detection approach according to the principles of the present invention, including excellent neutron:gamma discrimination and directionality.
The present detector invention enables portability, low cost, real time signal capability, complete integration with silicon microdevice technology and internet network connectivity. The present device approach, for the first time, combines a directional optical converter (neutrons to secondary electrons to light) with state-of-the-art optoelectronic detection to provide a digital output which is compatible with wireless reporting protocols, in an “Internet of Everything” scenario. The present device can therefore be reconfigured for many radiation detection tasks that are currently not feasible with larger, bulky devices using conventional gas proportional detector technology. This invention therefore opens up new opportunities for a class of compact, cost-effective neutron detectors. The invention is at the forefront of neutron detection science, for the first time utilizing radiation response of a high density of large capture cross-section B-10 nuclei in a high-purity glass network.
The broader impact of the present teachings is the potential to bring a disruptive neutron detector technology to market, filling an urgent demonstrated need for real time, portable and wearable radiation detectors. Successful implementation of this innovative technology will serve a broad customer need in the nuclear detection and verification industry. Customer channels include homeland security personnel, first responders, nuclear power industry workers, airline staff and national lab staff, all of whom need a capability to detect the presence of both naturally occurring and neutron emitting radioactive materials, and to assess the health physics risk in real time.
Market research indicates large scale potential for this invention. This market is currently well served with gamma ray and x-ray detection devices, but the capabilities for wearable neutron dosimeters are not as well established at this time. The present teachings will close this gap and is anticipated to have a very broad impact. The Čerenkov detector technology can also be transformative in enabling new kinds of directional arrays for neutron imaging and portal detectors, helping to make the nation's borders more secure against illicit nuclear materials and providing improved tools for nuclear safeguards and verification.
The present teachings is based on an optoelectronic detection mechanism such that neutrons interacting with a large capture cross section nucleus (Boron-10) produce secondary charged particles (energetic electrons) which then emit light, either by fluorescence (scintillation) or by the Cerenkov effect. This light is then detected by a sensitive photodetector (photomultiplier tube, p-i-n diode, or avalanche photodiode, or Charge coupled device or CMOS imager).
The present teachings, in some embodiments and in various combinations, employ all-solid-state optoelectronics technology, use a boron-loaded glass (like borosilicate glass) as a neutron capture/scattering medium, use of Čerenkov radiation to make fast neutrons visible to the photodetector, employ directional neutron detection because Čerenkov radiation is emitted in a cone paraxial with the direction of the incident neutron (unlike scintillation which is isotropic), can be fabricated without the need for a clean room or complicated lithography, and employ components that are largely off-the-shelf.
The present teachings may find utility in a wide variety of applications and/or personnel, including, but not limited to, homeland security, detection of special nuclear materials, border protection authorities, coastguard personnel, military personnel, nuclear power workers, airline crew, and oil well logging for hydrocarbon content and environmental contamination assessments.
The present teachings may further provide a number of advantages over conventional systems, including, but not limited to, all-solid-state providing a compact structure compared to gas proportional detectors, real-time notification of neutron radiation danger, off-the-shelf components, wirelessly networkable and fully integrated with silicon microelectronics, compatible with the internet of things, directional in order to image neutron source location, fast pulse signal for using pulse shape discrimination for gamma rejection, low voltage/low power operation, simple manufacturing processes, and convenient integration with solid state gamma radiation detectors.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.